Thanks Tkamiya for asking and Ken this sounds like a good idea.
Originally Posted by Ken Nadvornick
When I used my Omegalite, there was a spongy foam interface between lamphead and negative carrier. I modified this sticky foam by covering it with some thin black 1.1 silnylon (leftover from some DIY backpacking gear projects).
But I recently switched to an Aristo Grid lamphead which uses a traditional condenser housing. I noticed that greenish light spilling out pretty dramatically... So I am looking for this same idea. Didn't want to use "felt" because I didn't want dust. But this is exactly what I was thinking would be required.